Induction-motor.



arranged to cut out the resistance automaticsenseo.

nutren sufrir l' irn- T FF@ CONWAY ROBNSQN, CF SCHENECTAID', Alt'ltr'ZREL SSGNOR TG GENERAL ELECTEIG COMANY, A CORPORTGN GF NEW YGBK.

IENDUCTION-MTR.

To all when?, it may concern.'

Specification of 'Letters Patent.

Application filed February i4, 1906.

[connections ot the rotor conductors that Patented. 9ct. t2, 199th...serial No. 301,025.

Be .it known that l, CONWAY RoerNsoN, e this distribution ot' themercury provides e sistenee should be short-circuited when the motor isupto speed. This short-circuiting` of the resistance may be done by handor automatically, and for this purpose centrifugally actuated switcheshave been sometimes employed heretofore, the rotor conductors-beingshort-circuited through' a resistsnce at starting and the switch beingally when the motor is up to speed` In orderthat these switches may beused, it has been customary heretofore to forin the rotor winding out ofcoils so that the rotor conductors may be connected directly inseriesandonly a smallnumber of terminals brought out for short-circuiting. Thiscoil construction is more expensive than what is known as thesquirrel-cage construction, which is employedjn motors which startwithout resistence in circuit, and in which the rotor Winding iscomposedk simply of bars ell connected together at opposite ends throughshort-eircuiting end-rings. This simple con# struction has presenteddiiiculties heretofore when it has been desired to have a resistance inthe rotor circuit at starting, since a switch adapted tor short-circuitindividually,a large number of bars is necessarily complicated. By myinvention it is possible, without a complicated starting switch, to4employ a squirrel-cage construction and yetto obtain the advantages ofa coil-wound rotor with respect to starting with a resistance in therotor circuit.

My invention consists in providing the motor with a rotary casingcontaining a conducting fluid, such as mercury, adapted to bedistributed around the periphery of the casing by centrifugal force asthe motor speeds up, and so arrangingf` the casing and under loadshouldv 'here a resistance included in the rotor cir cui-t, if itis'desired to prevent it from drew j' ing a heavy starting current, andthis .re-

lowresistance short-circuit tor all the conductors individually, as in asquirrel-cage winding, when the vmotor is up to speed. l'. 'furtherprovide ineens for retarding the peripheral distribution of the mercuryso es to obtain the proper time element i'n operation.

More specically stated, my invention consists in providing the motorwith a casing carried by the rotor and formingr a high re sistanceshort-circuit for the rotorA conductors and a conducting'tluid ip"theeasing adapted to form e low-resistance shoitcircuit for the conductorswhen distributed around the inner periphery of the casing by centrifugalforce.

My invention comprises a number of other features which will best be.understood by reference to the accompanying drawings, in

AFigure l shows a side elevation, partly in eross-section, of a rotorprovided` with an automatic starting device in accordanceewith myinvention; and Fig. 2 shows an end elevation in cross-section, of thestarting device.

In the drawings A represents the stator of the motor, which carries theusual primary Winding,l a. Brepresents the rotorstructure which carriesthe rotor conductor b, which consists ot bars supported in the usualmenner in slots in' the laminations at the periphery of the rotorstructure. The. bars are all'directly connected to each other at one endby short-circuitiug rin-gs C. At the other end of the rotor the rotoroars are short-eircuilted `by a member D, which is bolt ed to the rotorstructure, endwhich serves as one of the clamping rings for holding therotor laminati-ons in place, and which is'in the form of an annulareasing. The rotor conductors b extend through the peripheral wall d ofthe casing close to its inner side. This wall, or, if it isnotinsulatedfrom the 'rest of the casing, the entire casing, is made i of highresistance metal, such, for instance, as manganese copper, and -forms ahighv resistance short-circuit for the rotor conductors atv starting.Within the casing Dis supported an annular trough E, which is carried onpins e close to the peripheral wall of the casing D. This trough isprovided with a re' strieted opening c in its periphery, es shown inFig. F, ,i`nl1`ig. 2, represents'a conleo lherinore, the device, iuuddition to being :uitonmtic in its action at starting, also.frutoninticully reacts itself for starting' again when the current iscut ott7 since, :is the rotor slows down7 the niercury Will collect ntthe lower portion of the casing.

lVbut. I cluiin ns new, and desire to secure by Letters Patent olE theUnited Sintes, is,

l. ln :in induction motorU n. rotor having u squirrel enge w hiding, uclosed casing carried :it one end of the rotor engaging the ends oit:ill the conductors of Huid Winding and Serving aS u high resistance endring for Suid Winding, und n conducting iluid in said Caising adaptedwhen distributed uround the inner periphery of seid casing tofurnish anadditional low resistance shortcircuit for Suid conductors and to :1ctelectrically :1S e. low resistance end ring therefor.

ln un induction niotor, u starting switch comprising n roluny casing', uConducting fluid therein, connections whereby the rotor conductors ureShorhcircuited by the distriried within the cuing; The n-'zills of thetrough E are arranged. 'to extend inward :i dielunce substuntiully equalto the depth of the inercury in the eosin casing is at rent, :is shownin Fig. l, so that when the crisi v et reet nearly ull the nier cury iscontained in the trough; only :i enroll portion being;` outeide ol thetroiufh und in contact with 'the peripheral wall d.

is the niotor te, the fluid F diS- tributed by centrifugal 'to 1e aroundthe :ixunulur trough E. )it Stnrtng, the rotor conductors areshort-circuil'ed only bythe high resistance casing, the Smell uniount ofinercury outside oi the trough short-circuiting only u few conductora,und not materially I allecting the operation. litter the mercury isdistributed uround the trough ll by cen triliugul force, it begins Lopues, outward through the restricted ooeninc' c, und to distributeitselt' around the inner periphery o' `the ending. ln this way, in:ulditionul Shortn i uxiinuni when the ducting lluiihsuch es mercury,which is our circuit or low resituncc i -i produced lor the bution orthe fluid around the inner periphrotor conductors through n lun' rcietnnce ery ol Suid casing by centrifugal 'torce7 und formed by themercury itself, und also by the ineens 'tor rcturding the distributionof the trough E, which inode of low-resistance tluid.

In un induction niotor7 u :starting switch comprising' u casing carriedby the rotor and foi-nung :1 high resistance short-circuit for the rotorconductors, Luid :i conductingfluid in said casing adapted to forni :ilow-resistance Shortfcircuit. `for Suid conductors when distributeduround the inner 'periphery of Suid easing by centrilugzilforce.

4. ln un induction motor, u Starting Switch comprising u casing carriedby the rotor und forming u higlrresistnnce Short-circuit Jor the rotorcoi'iductors, u conducting fluid in Suid casini; udnoted to forni nlow-resistance Short-circuit 'tor Suid conductors when distrilnitedaround the inner periphery or' Suid rinsingv by ccntritugnl force, undineens for returding the distribution oi said luid.

5. ln :in induction motor, LI-Sturting switch coniprieing u casing i bythe rotor und material, :unl which is placed in electrical connection,with ull the conduct/orsA Z; by the mercury iillinu the ,eprice betweenthe trough und the peripheral wull (Z. 'l he tiine Which elztpsesbetween the starting oi the motor und u completo short-circuiting of ellthe' rotor conductors by the mercury is deterniincd by the si' or' therestricted opening c', und consequently uuty readily be mede Whitt.-ever desired. l he cmiductorn` 7 :ire pli ced clone enough to the innerside ot the w ll l so 'that the reintuncc- :e little riferiti-,r thun ifthe mercury were in du ort commet with these ronductors? und thieronntrui ion rcudera it unnecessary to innige u, fluid-tight jointbetneenveuch conductor und the cunin would Abe necesnr) iii the condnctors extended into the clnnnber within the casing so us to coinc intodirect contuct with the mercury.

.lf lthe casingis built up ol' seperate ports, for eonienicuce inuesenibliuq, {luid-tight joint between the parte "nay be obtained bfinishing the contact Surface "I i curing thorn toim her, ;'o\ fj their:mixture oi: lithorge und glycerin. The con struction of the onda-ingmay, oi course, be varied as desired.

1With a motor :is thus constructed the udi'untuges of a c iiln'onn,drotor :irc obtained, as reguds the amount or stnrtingrurrent taken, withthe cheupuess :rofl simplicity oit construction of e squirrel-enge.Furthern'ioriu since the starting device is entirely l :iutoinuticT theniotor muy be installed in un l inucceusible position end Started bynierely l closing u switch in the p 'imftry circuit loczited wherever ismost convenient. Furcarried forming n high-resistance short-circuit 'jorthe rotor conductors, said conductors extending into the peripheral wallof sind casing close to its inv-er side, and :i conducting fluid in Said:using adapted around the inner periphery of Suid raining by centrifugalforce unil thereby to torni n lowresistunce Sliort-circuit for the rotorconductors.

G. ln an induction motor, :i storting switch comprising' u casingcarried by the rotor und formingA u high-resistance short-circuit forthe rotor eomluctors, seid conductors extendinginto the peripheral wallof Suid casing close to its inner side` u coinlucting fluid in Suidcasing adopted to be distributed Around the inner periphery of Suidcasing luy-centrifugal Jforce and thereby to forni u lowto bedistributed 'annular trough for the 1otor confor retarding the distriresistance short circuit ductors, and means bution of said iuid.

7 In an induction motor, a starting switch comprising a casing carriedby the rotor and forming a high-resistance short-circuit for the rotorconductors, a conducting fiuid in said casing adapted to be distributedaround the inner periphery of said casing by centrifugal force andthereby to form a loW- resistance short-circuit for the rotorconductors7 and an annular trough carried Within said easing` an dhaving a restricted opening in its periphery. 1

8. in an induction motor, a starting switch comprising a casing carriedby the rotor and forming a high-resistance short-circuit for the rotorconductors7 a conducting fluid in said casing adapted to be distributedaround `the inner periphery of-said casing by centrifugal force andthereby to form av low-resistance short-circuit for the rotorconductors, and an ot' low pressure material carried Within and closetothe inner periphery of said casing and having a restricted opening inits periphery.

S). In an induction motor, a starting switch comprising a easingearriedby the rotor and forming a high-resistance shortecircuit for' the rotorconductors, a conducting tluidin said casing adapted to be distributedaround the .inner'periphery-of said casing by centrifugal force andthereby to form a 10W` resistance short-circuit for the rotorconductors, and an annular. trough carried Within said casing, its sidesextendingin- Ward a distance substantially equal to the maximum depth ofsaid fluid in said casing when said casing is stationary, said troughhaving a restricted opening in its periphery.

In an induction motor, a starting switch comprising a casing carried-bythe rotor and forming a high-resistance .shortcireuit for the rotorconductors, said conductors extending into the peripheral Wall of saidcasing close to its innerside, a conductingluid in said easing adaptedto be distributed around the inner periphery of-said i l l l I l to forma lowresistaiice short-circuit for the rotor conductors, and an annulartrough for low-resistance material carried Within and close to the innerperiphery of said casing and having a restricted opening in itsperiphery.

l2. In an induction motor, a laminated i'otor body, an end-ring forclamping the aminations in place in nular casing, conductors carried bythe rotor connected at one end to said-ring, vsaid 4ring being adapt-edto form a high-resistance short-circuit for said conductors, and aconducting fiuid Within said end -ring adapted to be distributed aroundits inner periphery by centrifugal force and thereby to form alow-resistance short-circuit for said conductors.

13. In an induction motor, a laminated rotor body, an end-ring forclamping the laminations in place in the form of an annular casing,conductorsv carried by connected at one end to said ring,

the form of'an anshort-circuit for said conductors, a conductcasing bycentrifugal force and thereby. to

form a low-resistance rotor conductors,

carried within said stru-.ted opening in short-circuit foi; alid anannular trough casing and having' a reits periphery. f

11.111 an induction motor, a starting switch comprising a casing carriedby the ing fluid Within said end-ring adapted to be distributed aroundits inner periphery by centrifugal force and thereby to form a lo'w- 90-resist-ance short-circuit for said conductors and means for. retardingthe distribution ot said Huid.

14. In an ,induction motor, a laminated rotor body,

an end-ring for clamping the laminations in place in the form of anannular casing, conductors carried by the rotor and extending into theperipheral ivall of said casing, said Wall being ada ted to formthigh-resistance short-circuit tor said eon- 100 ductors, vand aconducting fluid Withinl said casing adapted to be distributed aroundits inner periphery by centrifugal force and thereby to -form alow-resistance short-cir cuit for said conductors.

15.111 an induction motor, a laminated rotor body, an end-ring forclamping the laminations in place in the form of an annular casing,conductors carried by the rotor and extending into the peripheral Wallof said casing, said wall being adapted to form a high-resistanceshort-circuit for said conductors, a conducting tluid within said casingadapted. toA bedistributed around its inner periphery by centrifugalforce and thereby to 'orin a low-resistance short-circuit for saidconductors, and means for retardingl the distribution of said iiuid.

ln witness whereof, l have hereunto set my hand this 13th day ofFebruary, 1906. 120

CONWAY ROBINSON.

lVitnesses:

BnNJAMiN B. Hur' HELEN Oni'onn.

